A technique for assigning plural functions to a single key (operation key) is known. The technique is commonly used in an information-processing device such as a mobile phone, in which a number of keys is limited. A key to which the technique is applied is referred to as a “soft key” (software key), since functions are assigned to the key for each piece of software.
When plural functions are assigned to a single key, functions assigned to the key can be displayed. If functions are displayed, a user can distinguish readily functions assigned to the key.